1. Field of the Invention
The present invention relates generally to an apparatus and method for compressing body tissue to prevent hemorrhaging at a surgical site within a patient's body. More specifically, the invention provides a clip and a system for delivering the clip to the surgical site. The present invention could be utilized for any of a variety of procedures, including to close an organ perforation from inside a lumen by approximating and compressing the wound edges of the perforated tissue.
2. Description of the Related Art
Bleeding Peptic Ulcer Disease can be a critical event since there is internal hemorrhaging associated with the ulcer. Patients that are suspected of having bleeding peptic ulcer disease can be diagnosed and treated endoscopically in emergency rooms of medical centers, intensive care units, or, in a Gastro-Intestinal (GI) suite, although personnel and equipment may need to be transported to the patient. Surgery, either laparoscopic or open, is an option. For example, if the diseased tissue is beyond repair, a surgical gastric resection may have to be performed. However, surgery is not preferred unless there is no endoscopic alternative or if previous endoscopic efforts have not succeeded. Surgical intervention is not preferred for at least the reasons that it has associated with it greater morbidity and mortality, and also, significantly higher costs than other procedures.
Ulcers are classified from clean ulcer to active spurting bleeding. The most worrisome are active bleeders and visible vessels. Untreated visible vessels are likely to bleed. For the GI endoscopist, hemorrhaging is the most worrisome procedure. It is his/her only unplanned, emergency procedure where time is critical in determining the success or failure of the procedure. It is the one problem the endoscopist faces that is generally not an outpatient procedure.
The endoscopist generally has a primary success rate of about 90% in treating bleeding ulcers; the balance are usually referred to surgery. All identified ulcers may re-bleed at a later time, whether endoscopically treated or untreated, but the re-bleed rate for endoscopically treated active bleeds and visible vessels is generally 10-30%. These rates have not improved significantly in decades.
The long-term probability of success of surgery in treating a bleeding ulcer, i.e., no re-bleed of the ulcer or permanent hemostasis, is virtually 100%. The reason that surgery has a higher success rate is because the bleeding site is compressed mechanically. Using either sutures or staples, the bleeding vessel is ligated, or tissue around the bleed site is compressed, ligating all of the surrounding vessels.
At present, the endoscopist has two widely, used, and some lesser used (or experimental) therapeutic modalities for hemostasis. The most widely used are thermal and injection therapy. Some of the lesser used options are a mechanical clip, a loop, lasers and argon plasma cautery. However, drawbacks exist with these known procedures for the endoscopist. A brief description of these procedures are provided below.
In thermal therapy, a catheter with a rigid, heating element tip is passed through a working channel of an endoscope after the bleed is visualized and diagnosed. After the rigid catheter tip has exited the endoscope, the endoscope is manipulated to press the tip against the bleed site. Thermal power is then applied which desiccates and cauterizes the tissue. The combination of the tip compressing the tissue/vessel during thermal application essentially (theoretically) welds the vessel closed. Thermal generation is accomplished by either a resistive element within the tip or by applying RF energy through the tissue. However, both methods require a specialized power generator.
For injection therapy, a catheter with a distally extendible hypo-needle is passed through a working channel of an endoscope after the bleed is visualized and diagnosed. After the catheter tip has exited the endoscope, the endoscope is manipulated to the bleed site, the needle is extended remotely and inserted into the bleed site. A “vasoconstricting”, liquefied drug is remotely injected through the needle. The drug constricts the vessels to stop the bleeding. The most common drug is saline diluted epinephrine; alcohol is another option. This procedure usually requires that multiple injections be performed in, and peripherally around, the bleeding site until hemostasis is observed.
Of the above two modalities, the preferred modality is dependent, generally, upon the geographic region in which it is performed. Different modalities are preferred in different geographic regions. In some areas and institutions, both therapies are combined in an attempt to improve the outcome of the procedure.
For mechanical compression, loops and mechanical clips are known for use, however, problems exist with each. A known loop is a snare-like loop that is passed through an endoscope's working channel via a flexible delivery catheter. The loop is placed around the bleeding site and retracted into the delivery catheter similar to the closing of a snare. The loop has a sliding member with a friction interface against the loop that acts like a draw string lock. After the loop is closed and locked around the site, the assembly is unattached from the delivery catheter. Whereas the loop is an endoscopically delivered compression device, its primary use is for bleeding polyp stalks, and thus, it is not designed for, nor appropriate for use in, ulcer treatment procedures. Specifically, the physical characteristics of an ulcer bed, such as its relatively flat geometry and the type of tissue comprising the ulcer bed, differ from those of a polyp such that the use of an endoscopically delivered loop for compression is inappropriate.
A mechanical clip is known, however, the known mechanical clip has drawbacks. The known clip is a two legged clip that is passed through an endoscope's working channel via a flexible delivery catheter. The jaws of the clip are remotely opened, pushed into the bleeding site, closed and detached. Because of the requirement to pass the clip through the endoscope, the clip's size must be limited which prevents the clip from being able to clamp off all of the vessels in the tissue around the wound. Additionally, the clip is not able to provide sufficient clamping force because of its structural design. Thus, these clips require multiple applications and are not effective for definitive hemostasis. An additional problem with these clips is that when delivering these clips to the wound site, good visualization of the bleeding vessel cannot be obtained. The endoscopist may be required to blindly attach the clip, resulting in an imprecisely preformed procedure that may require guess work on the part of the endoscopist.
Therefore, it would be desirable to provide an improved system and method for endoscopically treating bleeding ulcers which could bring the initial hemostasis success rate for the endoscopic procedure in-line with the success rate achievable in surgical procedures. This system and method would provide for an improved capability to mechanically compress the bleeding site to achieve an effect which is commensurate with that obtainable in a surgical procedure.